JP5165638B2 - Electrolytic capacitor - Google Patents

Description

  The present invention relates to an abnormality sensing / safety type electrolytic capacitor in which electrodes (1+, 1-) are short-circuited when an internal pressure rises due to deterioration or when an abnormality occurs in an electrolytic capacitor used in various electronic devices.

  FIGS. 8A and 8B are a sectional view and a perspective view showing the configuration of a screw terminal type aluminum electrolytic capacitor (hereinafter simply referred to as an electrolytic capacitor) as an example of this type of conventional electrolytic capacitor. 8, the capacitor element 6 is constructed by winding an electrolytic paper 9 between an anode foil 8 and a cathode foil 7 and affixing a winding stop tape 5 to a winding end portion. The element 6 is impregnated with a driving electrolyte solution (not shown).

  The metal case 4 is a bottomed cylindrical metal case that accommodates the capacitor element 6. After the capacitor element 6 is accommodated in the metal case 4, the sealing terminal plate 2 is placed in the groove provided on the side surface of the metal case 4. The metal case is configured to be sealed by drawing (curling) for fitting the open end of the metal case to the rubber portion of the sealed terminal plate.

  FIG. 9 is a plan view (FIG. 9A) and a cross-sectional view (FIG. 9B) showing a detailed configuration of the sealing terminal plate 2 of the electrolytic capacitor shown in FIG. As shown in FIG. 9, the sealing terminal plate 2 is provided with a pressure valve 10 made of thin rubber. When the internal pressure rises due to deterioration of the electrolytic capacitor, the thin rubber portion of the pressure valve 10 is expanded to a certain level or more. The rubber part is broken by the internal pressure, and the internal gas is allowed to escape.

  In addition, Patent Document 1 and Patent Document 2 disclose an electrolytic capacitor having a configuration in which a pressure release valve made of silicon rubber or the like is provided on a sealing plate of a case to leak pressure against an increase in internal pressure.

2007-142252 No. 2008-10476

  As described above, when an electrolytic capacitor is subjected to a load for a long period of time, gas is generated due to deterioration, the internal pressure is increased, the capacitance is reduced, and the function as a capacitor is not achieved. As a result, there has been a problem that an unexpected effect such as malfunction of the apparatus occurs.

  Also, in the conventional configuration that suppresses the increase in internal pressure by leaking pressure, the increase in internal pressure is suppressed so that the capacitor does not rupture, but the life of the capacitor is reached compared to the device provided with the capacitor. There is a problem that it is difficult to notify the fact that the device is operating as it is, and malfunctions.

  Accordingly, an object of the present invention is to provide an electrolytic capacitor capable of causing a device provided with the electrolytic capacitor to sense the occurrence of abnormality of the electrolytic capacitor when an internal pressure increases due to deterioration or when an abnormality occurs. .

  The electrolytic capacitor of the present invention is a sealed terminal plate having an electrode short-circuit mechanism in which an electrolytic solution is impregnated into a capacitor element wound through an electrolytic paper between an anode foil having a chemical conversion film and an opposing cathode foil. Is an electrolytic capacitor formed by drawing (curling) the sealing terminal plate and the metal case after being housed in the metal case, and formed on the sealing terminal plate. A bell-shaped through hole having a second annular convex part, a pressure rubber having a convex cross section having a shoulder part and a neck part inserted into the through hole, and a short ring fitted to the neck part of the pressure rubber, It has a cross-sectional knife-edge shaped end that is located above the second annular convex part of the through hole and is exposed in the through hole so that the obliquely cut end surface faces the second annular convex part. And first and second electrodes facing each other When the internal pressure of the electrolytic capacitor increases, the pressure rubber shoulder rises beyond the second annular protrusion from the state where the pressure rubber is engaged with the first and second annular protrusions, and the pressure rubber An electrode short-circuit mechanism is provided, in which a short ring fitted to the neck portion is brought into contact with the first and second electrodes (1+, 1-) to short-circuit the two electrodes.

  When the electrode is short-circuited, the shoulder of the pressure rubber rises beyond the second annular convex portion, and the lower portion of the shoulder is fitted to the second annular convex portion. The combined short ring is maintained so that it does not come out of contact with the electrode (1+, 1-), the short circuit between the electrodes (1+, 1-) is reliably detected, and the fuse of the device mounted with the capacitor is connected. Can be cut and stopped safely.

  According to the electrolytic capacitor of the present invention, when the internal pressure rises due to deterioration or when an abnormality occurs, the electrolytic capacitor can reliably cause the device provided with the electrolytic capacitor to detect the increase in internal pressure of the electrolytic capacitor and the occurrence of abnormality. Can be provided.

It is the schematic cross section of the electrolytic capacitor which concerns on embodiment of this invention, and a capacitor | condenser element structure figure. It is a top view which shows the detailed structure of the sealing terminal board with a short mechanism of the electrolytic capacitor of FIG. 1, and sectional drawing by the BB line of the said top view. It is a fragmentary sectional view which expands and shows the attachment part of pressure rubber provided as a short mechanism. It is a fragmentary sectional view showing the state where pressure rubber rose by internal pressure. It is a top view which shows a pressure rubber. It is a top view which shows the short ring fitted by the pressure rubber. It is a graph which shows the short state between electrodes at the time of internal pressure rise. It is a schematic cross section of a conventional electrolytic capacitor and a capacitor element structure diagram. It is a top view which shows the detailed structure of the sealing terminal board of the electrolytic capacitor of FIG. 8, and sectional drawing by the AA line of the said top view.

  FIGS. 1A and 1B, in which parts corresponding to those in FIG. The electrolytic capacitor shown in FIG. 1 is different from the electrolytic capacitor shown in FIG. 8 in that a sealing terminal plate 22 with a short mechanism is provided.

  As shown in FIG. 1, in the electrolytic capacitor according to the present embodiment, the capacitor element 6 is wound with the electrolytic paper 9 interposed between the anode foil 8 and the cathode foil 7, and an anti-winding tape is provided at the winding end portion. The capacitor element 6 is impregnated with a driving electrolyte solution (not shown).

  The metal case 4 is a bottomed cylindrical metal case that houses the capacitor element 6, and the sealing terminal plate 22 is a pair of terminals 1 to which the lead tab 3 for external lead drawn from the capacitor element 6 is connected. It has.

  The sealing terminal plate 22 is disposed in the opening of the metal case 4 and seals by curling the open end of the metal case 4, thereby ensuring the airtightness of the electrolytic capacitor. . The sealing terminal plate 22 is provided with a through hole 22A in the center thereof, and a pressure rubber 11 and a short ring 12 (FIGS. 3 and 4) described later are provided as a short mechanism.

  Next, a method for manufacturing the electrolytic capacitor according to the present embodiment will be described. First, after connecting the lead tabs 3 for the external lead to the anode foil 8 and the cathode foil 7 respectively, the sheet is wound with the electrolytic paper 9 interposed between the anode foil 8 and the cathode foil 7, and the winding-stop tape is attached to the end of the winding. The capacitor element 6 is produced by pasting 5.

  Next, after impregnating the capacitor element 6 with the driving electrolyte, the lead tab 3 drawn out from the capacitor element 6 is attached to the pair of terminals 1 provided on the sealed terminal plate 22 that has been subjected to concave threading. Connect each one.

  Next, the capacitor element 6 and the sealing terminal plate 22 with a short mechanism are accommodated in the metal case 4 and curled.

FIGS. 2A and 2B are a plan view (FIG. 2A) and a cross-sectional view (FIG. 2B) showing a detailed configuration of the sealing terminal plate 22 with a short mechanism of the electrolytic capacitor according to the present embodiment.
3 is an enlarged partial cross-sectional view showing a mounting portion of the pressure rubber 11 with a short function provided as a short mechanism, and FIG. 4 is a partial cross-sectional view showing a state in which the pressure rubber 11 is raised by internal pressure. It is.
5 is a plan view showing the pressure rubber 11, and FIG. 6 is a plan view showing a conductive short ring 12 fitted to the pressure rubber 11. As shown in FIG.

  As shown in FIGS. 2 and 3, the sealing terminal plate 22 has a through hole 22 </ b> A. The through hole 22A has a bell-shaped large-diameter portion 22B having a large inner diameter, and a small-diameter portion having a smaller inner diameter than the large-diameter portion 22B communicated with the large-diameter portion 22B in the ceiling portion of the large-diameter portion 22B. 22C.

  The large-diameter portion 22B has a first annular convex portion 22D projecting into the through hole 22A at the lower portion thereof, and a second annular convex portion 22E projecting into the through hole 22A at the upper portion thereof. Is formed.

  The first electrode 1 (−) and the second electrode 1 (+) protrude from the boundary portion between the large diameter portion 22B and the small diameter portion 22C of the through hole 22A—the upper portion of the second annular convex portion 22E. A collar portion 1A is formed. The end portion 1B of the flange portion 1A has a knife edge cross section, and is exposed and disposed in the through hole 22A so that the end surface that is cut obliquely faces the second annular convex portion 22E side.

  The end portions 1B of the first electrode 1 (-) and the second electrode 1 (+) face each other across the internal space of the through hole 22A at the boundary between the large diameter portion 22B and the small diameter portion 22C. Are arranged as follows.

  The pressure rubber 11 is inserted into the through hole 22A. The pressure rubber 11 is formed in a columnar shape having a convex cross section, and has a lower portion 11A having a large diameter and an upper portion 11B having a small diameter. A step is formed from the shoulder 11C of the lower portion 11A to the neck 11D which is the base of the upper portion 11B, and an annular short ring 12 is fitted to the neck 11D.

  As shown in FIG. 3, in a state where the lower portion 11A of the pressure rubber 11 is engaged with the large diameter portion 22B of the through hole 22A, the lower portion 11A is the first formed on the large diameter portion 22B of the through hole 22A. The movement in the vertical direction is restricted by the annular projection 22D and the second annular projection 22E.

  In this state, when the internal pressure of the electrolytic capacitor rises, as shown in FIG. 4, the shoulder portion 11C of the pressure rubber 11 rises beyond the second annular convex portion 22E, and the short ring 12 fitted to the neck portion 11D. However, the first electrode 1 (−) and the second electrode 1 (+) come into contact with the flange portion 1A (end portion 1B) to short-circuit the electrodes 1 (−) and 1 (+).

  This short-circuit state makes it possible to detect the occurrence of a capacitor abnormality in a device provided with the electrolytic capacitor.

  In the case of the present embodiment, the end portion 1B of the flange portion 1A is formed in a knife edge shape that is cut obliquely so that the protruding amount in the lateral direction increases toward the upper portion, and the first electrode 1 The distance L1 between the edge portion of the end portion 1B of (−) and the edge portion of the end portion 1B of the second electrode 1 (+) is formed smaller than the outer diameter L2 of the short ring 12. As a result, when the pressure rubber 11 rises, the short ring 12 reliably contacts the end portions 1B of the first electrode 1 (−) and the second electrode 1 (+).

  At this time, the shoulder portion 11C of the pressure rubber 11 rises over the second annular convex portion 22E, and the lower portion of the shoulder portion 11C of the pressure rubber 11 is fitted to the second annular convex portion 22E. The short ring 12 fitted to the neck portion 11D of the rubber 11 is maintained so as not to come off the electrode (1+, 1-) contact position.

  Further, the peripheral side surface of the lower portion 11A is inclined so that the diameter decreases upward, and the through hole 22A of the sealing terminal plate 22 is formed so that the diameter decreases toward the upper portion in accordance with this. Thereby, the rise of the pressure rubber 11 is suppressed until the internal pressure of the electrolytic capacitor reaches a predetermined value.

  In addition, when it is made to suppress the raise of the said pressure rubber 11 only by the elasticity of the pressure rubber 11 until an internal pressure becomes a predetermined value, the inclination of the lower part 11A and the through-hole 22A becomes unnecessary.

  Hereinafter, specific examples of the present invention will be described.

  As the electrolytic capacitor shown in FIG. 1, an evaluation test (internal pressure increase test) was attempted using phenol resin for the sealing terminal plate 22 and silicon and EPT rubber for the pressure rubber 11, and the results shown in FIG. 7 were obtained.

  As shown in FIG. 7, the sealing terminal plate 2 to which the conventional pressure valve 10 is attached remains applied with voltage only for mechanical operation, but the pressure rubber 11 and the short ring 12 according to the embodiment of the present invention. In the sealed terminal board 22 with a short function, to which an electrical pressure is attached, an electrical operation due to an increase in internal pressure is applied, and a short circuit is detected.

  As described above, in the electrolytic capacitor according to the present embodiment, when the internal pressure rises, the pressure rubber 11 rises and the short ring 12 contacts the electrodes 1 (−) and 1 (+). Short-circuit between (−) and 1 (+), and the state is maintained.

  As described above, before the function of the capacitor is not sufficiently performed due to the increase in internal pressure, the terminals are short-circuited, and the fuse (not shown) of the device provided with the electrolytic capacitor can be disconnected, As a result, the device can be safely stopped before the device malfunctions.

  That is, before the function as an electrolytic capacitor is lowered to such an extent that the device malfunctions, the fuse of the device can be cut and the device can be safely stopped.

  In the above-described embodiments, the case where the present invention is applied to an electrolytic capacitor in which the valve metal is aluminum is described. However, the present invention is not limited to this, and a valve metal such as tantalum or niobium is used instead of aluminum. Even if the present invention is applied to those used in the above, the same effect can be obtained.

  Further, in the above-described embodiment, the case where phenol resin is used as the material of the sealing terminal plate 22 and silicon or EPT is used as the material of the pressure rubber 11 is not limited to this. Other materials can be used as long as they work.

1 terminal 1A collar 1B end 2, 22 sealing terminal plate 3 lead tab 4 metal case 5 winding tape 6 capacitor element 7 cathode foil 8 anode foil 9 electrolytic paper 10 pressure valve 11 pressure rubber 11A lower 11B upper 11C shoulder 11D neck 12 Short ring 22A Through hole 22B Large diameter part 22C Small diameter part 22D First annular convex part 22E Second annular convex part

Claims (1)

Capacitor element wound via electrolytic paper between anode foil with chemical conversion film and opposing cathode foil is impregnated with electrolyte, and a sealed terminal board with electrode short-circuit mechanism is attached and stored in a metal case After that, an electrolytic capacitor formed by drawing a sealed terminal plate and a metal case,
A bell-shaped through hole formed in the sealing terminal plate, having a first annular convex portion at the lower portion and a second annular convex portion at the upper portion,
A pressure rubber having a convex cross section having a shoulder and a neck, inserted into the through hole;
A short ring fitted to the neck of the pressure rubber;
A cross-sectional knife-edge shaped end disposed above the second annular convex portion of the through hole and exposed in the through hole so that an obliquely cut end surface faces the second annular convex portion side A first electrode and a second electrode facing each other,
An electrolytic capacitor comprising:

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